(1) Field of the Invention
The present invention relates to a light-emitting apparatus in which a light-emitting region having a larger area is formed by arranging a plurality of light-emitting panel units each having a light-emitting portion.
(2) Description of Related Art
In recent years, light-emitting apparatuses such as display apparatuses and illumination apparatuses have been increasing in size. Particularly, with the progress of the development of organic EL elements, it is expected that light-emitting apparatuses for surface light sources will be realized as illumination and that large-size display light-emitting apparatuses will be realized which enable high image quality, wide viewing angles, and low-power driving.
In general, a light-emitting apparatus such as a display apparatus or the like is treated as a defective item if only a small defect is present in a light-emitting region. In a light-emitting apparatus such as an illumination apparatus or the like, a defect also affects the quality of the illumination apparatus. Thus, in manufacturing a large-size light-emitting apparatus, a large-area light-emitting region provided by arranging a plurality of light-emitting panels formed as units has the advantage that the apparatus can be manufactured with a higher yield over a large-area light-emitting region provided by using a single large-size light-emitting panel. On the other hand, when the large-area light-emitting region is provided by using a plurality of light-emitting panels formed as units and a non-light-emitting region is present at a joint between the light-emitting panels, the resulting non-light-emitting region extends in a mesh shape over the entire light-emitting region to present the problem of unnaturalness of a displayed image or illumination from a surface light source. Especially when the number of light-emitting panels formed as units is increased, leading of electrodes for supplying power or the like to a light-emitting portion is difficult, which contributes to a non-light-emitting region remaining in frames of light-emitting panel units.
A known method of making joints between light-emitting panel units unobtrusive is to adjust projected images optically. For example, Patent Document 1 has described a small-size display for a cellular phone in which a lens is placed on a lower surface of a screen to magnify light emitted by a light-emitting element to make joints unobtrusive. In addition, for example Patent Document 2 has described a display apparatus in which display panels are connected with transparent joints interposed therebetween and an image is displayed optically on the transparent joints. Each of the display apparatuses described in Patent Documents 1 and 2, however, has the problem of requiring an optical apparatus for displaying an image on the joints between the panels which results in a complicated apparatus structure and an increased manufacture cost with upsizing of a screen.
Another method of making joints unobtrusive is described, for example, in Patent Document 3 in which a flexible substrate having an extended portion serving as a non-display region formed on a side of a rectangular display region is used and the extended portion as the non-display region is bent and connected electrically to a printed back-face substrate. In addition, Patent Document 4 has described the use of a substrate similar to that in Patent Document 3, in which an extended portion serving as a non-light-emitting region is placed over a back-face side of an adjacent display panel. In the structures described in Patent Documents 3 and 4, however, a non-display region remains in joints.
Another method of making joints unobtrusive is to bend a display region to make joints more unobtrusive as described in Patent Document 5 and Patent Document 6. However, formation of a seal portion on a frame of a display panel as in Patent Document 6 increases the size of an interval between adjacent display portions and is not sufficient to make joints unobtrusive. When an end portion of one of adjacent panels is bent for connection as in Patent Document 5, a gap is produced between adjacent panels, and this approach is not sufficient to make joints unobtrusive. In addition, Patent Documents 5 and 6 have not described a connection structure of signal transmission lines for display and power supply lines, and thus it cannot be necessarily said that    Patent Document 5 or 6 provides an effective technique for connecting numerous display panels to form a large screen.    Patent Document 1: Japanese Patent Laid-Open No. 2001-350428    Patent Document 2: Japanese Patent Laid-Open No. 2002-520672    Patent Document 3: Japanese Patent Laid-Open No. 2005-242148    Patent Document 4: Japanese Patent Laid-Open No. 2005-123153    Patent Document 5: Japanese Patent Laid-Open No. 2002-297066    Patent Document 6: Japanese Patent Laid-Open No. 2001-057288